Research suggests British parents now see alcohol, drugs and sex as part of growing up. Photograph: Rex Features/Image Source

British parents are increasingly relaxed about their children drinking alcohol from as young as 10 years old, taking drugs and having sex, according to research released today .

One-third of parents – rising to half of those in London – said they were happy for their children to experiment with cannabis. A similar proportion admitted they were relaxed about all drug-taking, regarding it as an inevitable part of growing up.

One-quarter of Londoners admitted they allowed their children to drink at home from the age of 10, whereas in Northern Ireland 15 was the average age.

The study of more than 3,000 parents across Britain also revealed that most are happy for their child to start having the occasional alcoholic drink at home from the age of 13.

"Sex, alcohol and even drugs are no longer no-go areas for children as far as parents are concerned," said Frank Furedi, professor of sociology at the University of Kent. "The old-fashioned parent is fast becoming a cultural minority as mums and dads do their best to give their kids the freedoms they did not have. Families have become surprisingly open-minded about allowing their children to experiment and find their own way in life.

"Parents understand that society has changed and that it is not the end of the world if their teenager experiments with alcohol or has sex," he added.

Parents were also liberal about homosexuality, with two-thirds saying they would have no problem if their child was gay.

Mothers showed themselves as being far more relaxed, with 76% saying they would be untroubled if their child was gay, – 55% – admitted they would feel uncomfortable if their child was homosexual.

There were also marked difference between mothers and fathers when it came to children drinking alcohol in the survey, commissioned to mark the DVD release of Modern Family.

Fathers are far more relaxed than mothers about drinking, with 17% of men happy with their child drinking at home from the age of 10 compared to just 6% of women. Fathers were also more liberal when it came to drug taking, with 38% seeing it as part of growing up compared to 24% of mothers.